Skydiving

Definition: Recreational and competitive sport parachuting, which arose from early twentieth-century barnstorming and military parachuting. Skydivers jump from aircraft, high buildings, or cliffs, or are towed by speedboats.

Significance: Skydiving is excellent recreation, lowering tension and providing good exercise. It is also a highly appreciated spectator sport.

As far as can be determined from the historical record, the parachute was originally conceptualized in the late fifteenth century by Leonardo da Vinci. About three centuries later, in 1783, the first functioning parachute was designed and operated by Louis-Sébastien Lenormand. It was a canopy, strengthened at the edge and using rigging to hold an underslung passenger basket. Lenormand tested his design with animal passengers first before using it to successfully jump from the Tour de la Babotte observatory in Montpellier, France. The first successful parachute jump from a high altitude was performed in 1797 by André-Jacques Garnerin, who used a modified Lenormand chute to jump from a hydrogen balloon at 3,200 feet. Nineteenth-century barnstorming parachutists similarly used Garnerin’s modified chutes to parachute from balloons. To provide greater thrills for spectators, folded and packaged canopies were developed. One outstanding chute was the Broadwick coat pack, designed by Charles Broadwick in 1901. It was worn like a jacket and fastened to the jumper's balloon (or, later, aircraft) by a static line designed so that as the parachutist fell, their weight pulled against the line and caused the canopy to open.

The first aircraft parachute jump was made by either Grant Morton in 1911, reportedly from more than 4,000 feet over Venice, California, or Captain Albert Berry in 1912, from 1,500 feet over Jefferson Barracks Military Post in Missouri. The first intentional free-fall parachute jump, in which the parachutist falls a significant distance from their aircraft before deploying their chute, was performed in 1914 by Georgia "Tiny" Broadwick, the adopted daughter of Charles Broadwick. She was demonstrating static-line jumps for the US Army when her static line became tangled with the airplane. For her next jump, she cut the line, leaving it long enough to hold in her hand, and waited to pull it until she was clear of the airplane. Even so, the military remained unconvinced that the human body could withstand free fall for more than just a few seconds until 1919 when Leslie Irvin and Floyd Smith demonstrated a parachute escape system they had designed for the US Air Force. Because aircraft that were falling out of control were unsuitable platforms for static-line systems, Smith and Irvin built free-fall packs with ripcords that let pilots control when the chutes opened. By the end of World War II, one hundred thousand aviators had been saved by parachutes, and paratroopers were routinely sent into battle.

Maria Yegella was the oldest person to solo parachute, jumping in October 2022 at the age of eighty-four years and 358 days. Don Kellner set the record for total jumps at 46,355 in 2021.

Basics of Sport Parachuting

In the 1950s, parachute modifications led to the development of steerable chute canopies, and people began to parachute for fun. Soon, changes in chute shape allowed for good horizontal movement, fine motion control, and soft, precise landings. The blank-gore parachute design, first used by British paratroopers during World War II, became popular among sport parachutists during this time. The blank-gore modification involves removing a panel (gore) from the hemispherical parachute canopy, allowing escaping air to be used to provide some thrust and direction via pulled steering lines attached to the bottom of the gore.

In 1961, Pierre-Marcel Lemoigne designed the first really steerable parachute, known as the ascending-gliding parachute; though intended as a training aid for military parachutists, it soon led to the development of recreational parasailing. Around the same time, Domina Jalbert was developing the parafoil, or ram-air parachute, which consists of inflatable rectangular “wings” that hugely increase canopy control. Their double surfaces (skins) are inflated by high-pressure air, producing the wing shape. Control is obtained by means of low-porosity canopy material; devices enabling the maximum use of canopy air; steering toggles to turn, brake, and control descent rate; and useful shroud-canopy connection systems at the front and rear of the chute. Overall venting arrangements of sport parachutes thus allow skydivers to fine-tune their descents after the canopy opens.

In skydiving, a jump is usually made from a slow-moving plane flying at altitudes between 10,000 and 12,000 feet. The skydiver remains in free fall until they reach 2,000 to 2,500 feet above the ground, at which point they deploy the parachute. Free-fall maneuvers are accomplished by controlling body position.

Competitive skydiving events include jumping for style, landing accurately, and performing in teams. Early contests in the 1930s involved only accuracy in landing on a target. The first world championship in skydiving was held in Yugoslavia in 1951 and involved contestants from five countries. After this event, world championship contests were scheduled every two years under the auspices of the Fédération Aéronautique Internationale (FAI). Modern parachuting world championships are organized by the FAI's International Parachuting Commission (IPC).

In jumping for style, the parachutists are required to perform stunts called aerobatic maneuvers, such as back turns, in the shortest time possible during free fall; they are judged on their aerobatic form, not on their landing site. In accuracy jumping events, competing parachutists seek to land as close as possible to the center of a circular target on the ground. In team events, members perform maneuvers known as relative work, such as baton passing or forming circles or other geometric figures. Each competing team attempts to form the largest number of patterns in the time available to them. In canopy relative work, team members link together and perform figures after their parachutes have opened.

In all competition jumping, the sport parachute is opened at an altitude designated by IPC judges. The way in which contestants leave the delivery aircraft is likewise predetermined. In most recreational skydiving, jumpers carry an altimeter, which indicates rate of descent and tells them when to open the chute. A newer variation on sport parachuting is BASE jumping, in which the parachutist jumps from fixed structures rather than an aircraft; the acronym BASE stands for the four broad categories of structures—building, antenna, span (bridge), Earth (cliff)—from which a parachutist can jump.

Sport Parachute Construction and Use

A skydiving parachute is manually opened with a ripcord after free fall, and the jumper rides it down to the ground. Each parachute is contained inside a knapsack-like harness container called a rig. In addition to the rig, other equipment includes altimeters, jumpsuits, helmets, and goggles.

Most parachutes used are ram-air chutes, named for the way in which they open and fly. The first ram-air canopies, which first became commercially available in the 1970s, used the same flight theory as do more modern canopies: the canopy leaves the rig, and the weight of the jumper causes it to inflate into a shape resembling an aircraft wing or airfoil. The canopy holds its airfoil shape because of two-skin (two-layer) construction, with the top and bottom skins joined at the rear, or trailing edge, and ends. The front, the parachute’s leading edge, is open to the air, and the canopy is divided into pockets or cells. Suspension lines between the skydiver and the canopy are shorter at the leading edge than at the trailing edge, causing the airfoil to tilt forward and move downward. Air is thus rammed into the cells, and as the jumper and chute move forward, the leading edge divides the air it meets so that air moves over the top skin faster than the air flowing under the lower parachute skin. This leads to lower pressure on the top surface than on the bottom, thus creating lift force, the mechanics that create flight. The canopy flies enough to make descent to the ground relatively slow, although the lift is not great enough to allow for ascent.

Canopy materials have changed frequently during the history of skydiving. Early canopies, later modified for sport parachute use, were made of silk. This gave them a small rig volume compared to the cotton or linen used by nineteenth-century parachutists, while still providing the strength and elasticity needed for fast opening. Silk was replaced with more durable and damp-resistant nylon soon after its invention in the 1930s. Most nylon in contemporary skydiving is the “ripstop” type used in many garments. Ripstop nylon resists tears because it is woven as many tiny squares, so that damage to any single square is contained within it. Shrouds (lines) that attach the jumper to the canopy need to combine strength and elasticity. Dacron, Kevlar, and zero-porosity (ZP) nylon are used to increase strength and reduce total rig weight for skydiver comfort. The greater the canopy porosity, the faster air passes through and the faster the chute falls. The use of ZP nylon slows the fall by allowing little air through the canopy.

Vertical (straight-ahead) ram-air flight is achieved by means of steering toggles situated above the parachutist’s right and left shoulders, into which the hands are inserted. The toggles connect to shrouds (suspension lines) in the canopy’s trailing edge and act like ailerons. Equal downward pull on both toggles distorts the trailing edge to slow the canopy’s vertical movement and descent rate, if the pull is not too radical. If, however, both toggles are depressed to waist level, full braking occurs, airspeed becomes negligible, and descent rate increases as the canopy loses its ability for lift. Turning a chute also uses the steering toggles. With one toggle depressed and the other unmoved, a full turn is produced in the direction of pull because the side of the canopy that is pulled slows down while the other side remains flying at speed.

To land, a sport parachutist faces into the wind because opposing airflow slows the parachute somewhat, making it easier to land on one’s feet. However, it does not affect the descent rate, which must be reduced to avoid a hard landing. A parachutist identifies the wind direction and turns directly into the wind by smoothly and quickly pulling down both toggles to slow the descent rate and forward speed. This converts the canopy’s forward speed, for an instant, to lift, during which time the parachutist steps down onto the ground. Maneuvering is complex and takes practice. However, student skydivers usually have the basics down after four to six hours of individual instruction.

Bibliography

Barthel, Christiane, et al. "Recreational Skydiving—Really That Dangerous? A Systematic Review." International Journal of Environmental Research and Public Health, vol. 20, no. 2, 2023, p. 1254. doi.org/10.3390/ijerph20021254.

Donaldson, Chris. Skydive: Sport Parachuting Explained. Crowood Press, 2000.

Haynes, Danielle. Skydiving. PowerKids Press, 2024.

Hearn, Peter. The Sky People: A History of Parachuting. 1990. Airlife Publishing, 1997.

Higgins, Matt. Bird Dream: Adventures at the Extremes of Human Flight. Penguin Press, 2014.

Meeks, Christopher. Skydiving. Capstone Press, 1991.

Poynter, Dan, and Mike Turoff. Parachuting: The Skydivers’s Handbook. 10th ed., Para Publishing, 2012.

Scheff, Matt. Skydiving. Pop!, a division of ABDO, 2020.

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